1. Field of the Invention
The present invention relates to a ceramic capacitor and a method for manufacturing the ceramic capacitor, and particularly to a multilayer ceramic capacitor having a structure in which external electrodes are arranged on a ceramic body including internal electrodes to be electrically connected to the internal electrodes, and to a method for manufacturing the multilayer ceramic capacitor.
2. Description of the Related Art
One representative ceramic electronic component is a multilayer ceramic capacitor as disclosed in Japanese Patent Laying-Open No. 2006-213946, for example.
As shown in FIG. 4, this multilayer ceramic capacitor has a structure including a ceramic stack (ceramic body) 110 in which a plurality of internal electrodes 102 (102a, 102b) are stacked with a ceramic layer 101 as a dielectric layer being interposed, and a pair of external electrodes 104 (104a, 104b) provided on a pair of end surfaces 103 (103a, 103b), respectively, of ceramic stack 110, wherein the pair of external electrodes (104a, 104b) are arranged to be electrically connected to internal electrodes 102 (102a, 102b).
External electrodes 104 (104a, 104b) are formed by, for example, baking a conductive paste containing a Cu powder as a conductive component. External electrodes 104 (104a, 104b) are also formed of sintered metal layers 105 (105a, 105b), which are formed to extend around from end surfaces 103 of ceramic body 110 to main surfaces and side surfaces thereof, and plating films 106 (106a, 106b) formed over the surfaces of sintered metal layers 105 (105a, 105b).
Note that plating films 106 (106a, 106b) include Ni-plating films 107 (107a, 107b) formed over surfaces of sintered metal layers 105 (105a, 105b), and Sn-plating films (108a, 108b) formed over Ni-plating films 107 (107a, 107b).
The above-described patent application publication describes that, according to the invention disclosed therein, a multilayer ceramic capacitor can be provided in which the Ni-plating films or the like are prevented from growing on surfaces of ceramic stack 110, and which includes external electrodes with excellent solder wettability.
The invention according to the above-described patent application publication, however, has a problem in that during the process of baking the conductive paste, diffusion of the metal material constituting the conductive paste into the internal electrodes may cause expansion of the internal electrodes, which, for example, may lead to cracks being formed from opposite end portions of uppermost and lowermost internal electrodes when seen from the end surface sides, toward the four corners of the ceramic body. Another problem is that reducing the temperature for baking the conductive paste in order to prevent the diffusion causes deterioration of the reliability of joining of the internal electrodes and the external electrodes.